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Zhan Y, Chen Q, Song Y, Wei X, Zhao T, Chen B, Li C, Zhang W, Jiang Y, Tan Y, Du B, Xiao J, Wang K. Berbamine Hydrochloride inhibits lysosomal acidification by activating Nox2 to potentiate chemotherapy-induced apoptosis via the ROS-MAPK pathway in human lung carcinoma cells. Cell Biol Toxicol 2023; 39:1297-1317. [PMID: 36070022 DOI: 10.1007/s10565-022-09756-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 08/26/2022] [Indexed: 01/18/2023]
Abstract
Autophagy is typically activated in cancer cells as a rescue strategy in response to cellular stress (e.g., chemotherapy). Herein, we found that Berbamine Hydrochloride (Ber) can act as an effective inhibitor of the late stage of autophagic flux, thereby potentiating the killing effect of chemotherapy agents. Lung carcinoma cells exposed to Ber exhibited increased autophagosomes, marked by LC3-II upregulation. The increased level of p62 after Ber treatment indicated that the autophagic flux was blocked at the late stage. The lysosome staining assay and cathepsin maturation detection indicated impaired lysosomal acidification. We found that Nox2 exhibited intensified co-localization with lysosomes in Ber-treated cells. Nox2 is a key enzyme for superoxide anion production capable of transferring electrons into the lysosomal lumen, thereby neutralizing the inner protons; this might explain the aberrant acidification. This hypothesis is further supported by the observed reversal of lysosomal cathepsin maturation by Nox2 inhibitors. Finally, Ber combined with cisplatin exhibited a synergistic killing effect on lung carcinoma cells. Further data suggested that lung carcinoma cells co-treated with Ber and cisplatin accumulated excessive reactive oxygen species (ROS), which typically activated MAPK-mediated mitochondria-dependent apoptosis. The enhanced anti-cancer effect of Ber combined with cisplatin was also confirmed in an in vivo xenograft mouse model. These findings indicate that Ber might be a promising adjuvant for enhancing the cancer cell killing effect of chemotherapy via the inhibition of autophagy. In this process, Nox2 might be a significant mediator of Ber-induced aberrant lysosomal acidification.
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Affiliation(s)
- Yujuan Zhan
- Department of Biochemistry, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
- Research Center of Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Qiugu Chen
- Department of Biochemistry, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
- Research Center of Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Yue Song
- Department of Biochemistry, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
- Research Center of Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Xianli Wei
- Department of Medical Instruments, Guangdong Food and Drug Vocational College, Guangzhou, 510520, People's Republic of China
| | - Tingxiu Zhao
- Department of Pathology, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Bonan Chen
- Department of Anatomical and Cellular Pathology, State Key Laboratory of Translational Oncology, The Chinese University of Hong Kong, Hong Kong, SAR 999077, China
| | - Chengxi Li
- Research Center of Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Wenbo Zhang
- Research Center of Integrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
- Department of Pathology, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Yanjun Jiang
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong, SAR 999077, China
| | - Yuhui Tan
- Department of Biochemistry, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Biaoyan Du
- Department of Pathology, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China
| | - Jianyong Xiao
- Department of Biochemistry, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China.
| | - Kun Wang
- Department of Pathology, Guangzhou University of Chinese Medicine, Guangzhou, 510006, China.
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Sebők-Nagy K, Blastyák A, Juhász G, Páli T. Reversible binding of divalent cations to Ductin protein assemblies-A putative new regulatory mechanism of membrane traffic processes. Front Mol Biosci 2023; 10:1195010. [PMID: 37228584 PMCID: PMC10203432 DOI: 10.3389/fmolb.2023.1195010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
Ductins are a family of homologous and structurally similar membrane proteins with 2 or 4 trans-membrane alpha-helices. The active forms of the Ductins are membranous ring- or star-shaped oligomeric assemblies and they provide various pore, channel, gap-junction functions, assist in membrane fusion processes and also serve as the rotor c-ring domain of V-and F-ATPases. All functions of the Ductins have been reported to be sensitive to the presence of certain divalent metal cations (Me2+), most frequently Cu2+ or Ca2+ ions, for most of the better known members of the family, and the mechanism of this effect is not yet known. Given that we have earlier found a prominent Me2+ binding site in a well-characterised Ductin protein, we hypothesise that certain divalent cations can structurally modulate the various functions of Ductin assemblies via affecting their stability by reversible non-covalent binding to them. A fine control of the stability of the assembly ranging from separated monomers through a loosely/weakly to tightly/strongly assembled ring might render precise regulation of Ductin functions possible. The putative role of direct binding of Me2+ to the c-ring subunit of active ATP hydrolase in autophagy and the mechanism of Ca2+-dependent formation of the mitochondrial permeability transition pore are also discussed.
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Affiliation(s)
- Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - András Blastyák
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Gábor Juhász
- Institute of Genetics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
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Wang Q, Wolf A, Ozkan S, Richert L, Mely Y, Chasserot-Golaz S, Ory S, Gasman S, Vitale N. V-ATPase modulates exocytosis in neuroendocrine cells through the activation of the ARNO-Arf6-PLD pathway and the synthesis of phosphatidic acid. Front Mol Biosci 2023; 10:1163545. [PMID: 37091866 PMCID: PMC10119424 DOI: 10.3389/fmolb.2023.1163545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/23/2023] [Indexed: 04/25/2023] Open
Abstract
Although there is mounting evidence indicating that lipids serve crucial functions in cells and are implicated in a growing number of human diseases, their precise roles remain largely unknown. This is particularly true in the case of neurosecretion, where fusion with the plasma membrane of specific membrane organelles is essential. Yet, little attention has been given to the role of lipids. Recent groundbreaking research has emphasized the critical role of lipid localization at exocytotic sites and validated the essentiality of fusogenic lipids, such as phospholipase D (PLD)-generated phosphatidic acid (PA), during membrane fusion. Nevertheless, the regulatory mechanisms synchronizing the synthesis of these key lipids and neurosecretion remain poorly understood. The vacuolar ATPase (V-ATPase) has been involved both in vesicle neurotransmitter loading and in vesicle fusion. Thus, it represents an ideal candidate to regulate the fusogenic status of secretory vesicles according to their replenishment state. Indeed, the cytosolic V1 and vesicular membrane-associated V0 subdomains of V-ATPase were shown to dissociate during the stimulation of neurosecretory cells. This allows the subunits of the vesicular V0 to interact with different proteins of the secretory machinery. Here, we show that V0a1 interacts with the Arf nucleotide-binding site opener (ARNO) and promotes the activation of the Arf6 GTPase during the exocytosis in neuroendocrine cells. When the interaction between V0a1 and ARNO was disrupted, it resulted in the inhibition of PLD activation, synthesis of phosphatidic acid during exocytosis, and changes in the timing of fusion events. These findings indicate that the separation of V1 from V0 could function as a signal to initiate the ARNO-Arf6-PLD1 pathway and facilitate the production of phosphatidic acid, which is essential for effective exocytosis in neuroendocrine cells.
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Affiliation(s)
- Qili Wang
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Alexander Wolf
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Sebahat Ozkan
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Ludovic Richert
- Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, CNRS UMR and Université de Strasbourg, Strasbourg, France
| | - Yves Mely
- Laboratoire de Bioimagerie et Pathologies, Faculté de Pharmacie, CNRS UMR and Université de Strasbourg, Strasbourg, France
| | - Sylvette Chasserot-Golaz
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Stéphane Ory
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Stéphane Gasman
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 and Université de Strasbourg, Strasbourg, France
- *Correspondence: Nicolas Vitale,
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Petrovszki P, Sebők-Nagy K, Páli T. The Activity of Native Vacuolar Proton-ATPase in an Oscillating Electric Field - Demystifying an Apparent Effect of Music on a Biomolecule. Front Mol Biosci 2021; 8:772167. [PMID: 34805280 PMCID: PMC8595334 DOI: 10.3389/fmolb.2021.772167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The effect of an oscillating electric field generated from music on yeast vacuolar proton-ATPase (V-ATPase) activity in its native environment is reported. An oscillating electric field is generated by electrodes that are immersed into a dispersion of yeast vacuolar membrane vesicles natively hosting a high concentration of active V-ATPase. The substantial difference in the ATP hydrolysing activity of V-ATPase under the most stimulating and inhibiting music is unprecedented. Since the topic, i.e., an effect of music on biomolecules, is very attractive for non-scientific, esoteric mystification, we provide a rational explanation for the observed new phenomenon. Good correlation is found between changes in the specific activity of the enzyme and the combined intensity of certain frequency bands of the Fourier spectra of the music clips. Most prominent identified frequencies are harmonically related to each other and to the estimated rotation rate of the enzyme. These results lead to the conclusion that the oscillating electric field interferes with periodic trans-membrane charge motions in the working enzyme.
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Affiliation(s)
- Pál Petrovszki
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
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Downregulation of ATP6V1A Involved in Alzheimer's Disease via Synaptic Vesicle Cycle, Phagosome, and Oxidative Phosphorylation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:5555634. [PMID: 33981384 PMCID: PMC8087993 DOI: 10.1155/2021/5555634] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/02/2021] [Accepted: 03/24/2021] [Indexed: 12/12/2022]
Abstract
Objective The objective of this study was to investigate the potential molecular mechanisms of ATPase H+ transporting V1 subunit A (ATP6V1A) underlying Alzheimer's disease (AD). Methods Microarray expression data of human temporal cortex samples from the GSE118553 dataset were profiled to screen for differentially expressed genes (DEGs) between AD/control and ATP6V1A-low/high groups. Correlations of coexpression modules with AD and ATP6V1A were assessed by weight gene correlation network analysis (WGCNA). DEGs strongly interacting with ATP6V1A were extracted to construct global regulatory network. Further cross-talking pathways of ATP6V1A were identified by functional enrichment analysis. Diagnostic performance of ATP6V1A in AD prediction was evaluated using area under the curve (AUC) analysis. Results The mean expression of ATP6V1A was significantly downregulated in AD compared with nondementia controls. A total of 1,364 DEGs were overlapped from AD/control and ATP6V1A-low/high groups. Based on these DEGs, four coexpression modules were predicted by WGCNA. The blue, brown, and turquoise modules were significantly correlated with AD and low ATP6V1A, whose DEGs were enriched in phagosome, oxidative phosphorylation, synaptic vesicle cycle, focal adhesion, and gamma-aminobutyric acidergic (GABAergic) synapse. Global regulatory network was constructed to identify the cross-talking pathways of ATP6V1A, such as synaptic vesicle cycle, phagosome, and oxidative phosphorylation. According to the AUC value of 74.2%, low ATP6V1A expression accurately predicted the occurrence of AD. Conclusions Our findings highlighted the pleiotropic roles of low ATP6V1A in AD pathogenesis, possibly mediated by synaptic vesicle cycle, phagosome, and oxidative phosphorylation.
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Xia Y, Liu N, Xie X, Bi G, Ba H, Li L, Zhang J, Deng X, Yao Y, Tang Z, Yin B, Wang J, Jiang K, Li Z, Choi Y, Gong F, Cheng X, O'Shea JJ, Chae JJ, Laurence A, Yang XP. The macrophage-specific V-ATPase subunit ATP6V0D2 restricts inflammasome activation and bacterial infection by facilitating autophagosome-lysosome fusion. Autophagy 2019; 15:960-975. [PMID: 30681394 DOI: 10.1080/15548627.2019.1569916] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Macroautophagy/autophagy is a conserved ubiquitous pathway that performs diverse roles in health and disease. Although many key, widely expressed proteins that regulate autophagosome formation followed by lysosomal fusion have been identified, the possibilities of cell-specific elements that contribute to the autophagy fusion machinery have not been explored. Here we show that a macrophage-specific isoform of the vacuolar ATPase protein ATP6V0D2/subunit d2 is dispensable for lysosome acidification, but promotes the completion of autophagy via promotion of autophagosome-lysosome fusion through its interaction with STX17 and VAMP8. Atp6v0d2-deficient macrophages have augmented mitochondrial damage, enhanced inflammasome activation and reduced clearance of Salmonella typhimurium. The susceptibility of atp6v0d2 knockout mice to DSS-induced colitis and Salmonella typhimurium-induced death, highlights the in vivo significance of ATP6V0D2-mediated autophagosome-lysosome fusion. Together, our data identify ATP6V0D2 as a key component of macrophage-specific autophagosome-lysosome fusion machinery maintaining macrophage organelle homeostasis and, in turn, limiting both inflammation and bacterial infection. Abbreviations: ACTB/β-actin: actin, beta; ATG14: autophagy related 14; ATG16L1: autophagy related 16-like 1 (S. cerevisiae); ATP6V0D1/2: ATPase, H+ transporting, lysosomal V0 subunit D1/2; AIM2: absent in melanoma 2; BMDM: bone marrow-derived macrophage; CASP1: caspase 1; CGD: chronic granulomatous disease; CSF1/M-CSF: colony stimulating factor 1 (macrophage); CTSB: cathepsin B; DSS: dextran sodium sulfate; IL1B: interleukin 1 beta; IL6: interleukin 6; IRGM: immunity-related GTPase family M member; KO: knockout; LAMP1: lysosomal-associated membrane protein 1; LC3: microtubule-associated protein 1 light chain 3; LPS: lipo-polysaccaride; NLRP3: NLR family, pyrin domain containing 3; PYCARD/ASC: PYD and CARD domain containing; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SNAP29: synaptosomal-associated protein 29; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TLR: toll-like receptor; TNF: tumor necrosis factor ; TOMM20: translocase of outer mitochondrial membrane 20; ULK1: unc-51 like kinase 1; VAMP8: vesicle-associated membrane protein 8; WT: wild type; 3-MA: 3-methyladenine.
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Affiliation(s)
- Yu Xia
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Na Liu
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xiuxiu Xie
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Guoyu Bi
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Hongping Ba
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Lin Li
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Jinxia Zhang
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xiaofei Deng
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Yao Yao
- b Department of Surgery, Tongji Hospital , Huazhong University of Science and Technology , Wuhan , China
| | - Zhaohui Tang
- b Department of Surgery, Tongji Hospital , Huazhong University of Science and Technology , Wuhan , China
| | - Binjiao Yin
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Jing Wang
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Kan Jiang
- c Lymphocyte Cell Biology Section , NIAMS, NIH , Bethesda , MD , USA
| | - Zhuoya Li
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Yongwon Choi
- d Perelman School of Medicine , University of Pennsylvania , Philadelphia , PA , USA
| | - Feili Gong
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - Xiang Cheng
- e Laboratory of Cardiovascular Immunology, Institute of Cardiology, Union Hospital , Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
| | - John J O'Shea
- c Lymphocyte Cell Biology Section , NIAMS, NIH , Bethesda , MD , USA
| | - Jae Jin Chae
- f Inflammatory Disease Section , NHGRI, NIH , Bethesda , MD , USA
| | - Arian Laurence
- g Translational Gastroentology Unit, Nuffield department of medicine, John Radcliffe Hospital , University of Oxford , Oxford , UK
| | - Xiang-Ping Yang
- a Department of Immunology , School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology , Wuhan , China
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Chromophore-Assisted Light Inactivation of the V-ATPase V0c Subunit Inhibits Neurotransmitter Release Downstream of Synaptic Vesicle Acidification. Mol Neurobiol 2018; 56:3591-3602. [PMID: 30155790 DOI: 10.1007/s12035-018-1324-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/17/2018] [Indexed: 10/28/2022]
Abstract
Synaptic vesicle proton V-ATPase is an essential component in synaptic vesicle function. Active acidification of synaptic vesicles, triggered by the V-ATPase, is necessary for neurotransmitter storage. Independently from its proton transport activity, an additional important function of the membrane-embedded sector of the V-ATPase has been uncovered over recent years. Subunits a and c of the membrane sector of this multi-molecular complex have been shown to interact with SNARE proteins and to be involved in modulating neurotransmitter release. The c-subunit interacts with the v-SNARE VAMP2 and facilitates neurotransmission. In this study, we used chromophore-assisted light inactivation and monitored the consequences on neurotransmission on line in CA3 pyramidal neurons. We show that V-ATPase c-subunit V0c is a key element in modulating neurotransmission and that its specific inactivation rapidly inhibited neurotransmission.
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8
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Valproate inhibits glucose-stimulated insulin secretion in beta cells. Histochem Cell Biol 2018; 150:395-401. [PMID: 30145684 DOI: 10.1007/s00418-018-1713-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2018] [Indexed: 10/28/2022]
Abstract
Valproate (VPA), an FDA approved anti-epileptic drug with a half-life of 12-18 h in humans, has been shown to perturb the vacuolar proton pump (vH+-ATPase) function in yeasts by inhibiting myo-inositol phosphate synthase, the first and rate-limiting enzyme in inositol biosynthesis, thereby resulting in inositol depletion. vH+-ATPase transfers protons (H+) across cell membranes, which help maintain pH gradients within cells necessary for various cellular functions including secretion. This proton pump has a membrane (V0) and a soluble cytosolic (V1) domain, with C-subunit associated with V1. In secretory cells such as neurons and insulin-secreting beta cells, vH+-ATPase acidifies vesicles essential for secretion. In this study, we demonstrate that exposure of insulin-secreting Min6 cells to a clinical dose of VPA results in inositol depletion and loss of co-localization of subunit C of vH+-ATPase with insulin-secreting granules. Consequently, a reduction of glucose-stimulated insulin secretion is observed following VPA exposure. These results merit caution and the reassessment of the clinical use of VPA.
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Hypoxia-Induced MicroRNA-210 Targets Neurodegenerative Pathways. Noncoding RNA 2018; 4:ncrna4020010. [PMID: 29657306 PMCID: PMC6027187 DOI: 10.3390/ncrna4020010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/22/2018] [Accepted: 03/26/2018] [Indexed: 12/13/2022] Open
Abstract
Hypoxia-regulated microRNA-210 (miR-210) is a highly conserved microRNA, known to regulate various processes under hypoxic conditions. Previously we found that miR-210 is also involved in honeybee learning and memory, raising the questions of how neural activity may induce hypoxia-regulated genes and how miR-210 may regulate plasticity in more complex mammalian systems. Using a pull-down approach, we identified 620 unique target genes of miR-210 in humans, among which there was a significant enrichment of age-related neurodegenerative pathways, including Huntington's, Alzheimer's, and Parkinson's diseases. We have also validated that miR-210 directly regulates various identified target genes of interest involved with neuronal plasticity, neurodegenerative diseases, and miR-210-associated cancers. This data suggests a potentially novel mechanism for how metabolic changes may couple plasticity to neuronal activity through hypoxia-regulated genes such as miR-210.
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Ferencz CM, Petrovszki P, Dér A, Sebők-Nagy K, Kóta Z, Páli T. Oscillating Electric Field Measures the Rotation Rate in a Native Rotary Enzyme. Sci Rep 2017; 7:45309. [PMID: 28345665 PMCID: PMC5366918 DOI: 10.1038/srep45309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/21/2017] [Indexed: 11/09/2022] Open
Abstract
Rotary enzymes are complex, highly challenging biomolecular machines whose biochemical working mechanism involves intersubunit rotation. The true intrinsic rate of rotation of any rotary enzyme is not known in a native, unmodified state. Here we use the effect of an oscillating electric (AC) field on the biochemical activity of a rotary enzyme, the vacuolar proton-ATPase (V-ATPase), to directly measure its mean rate of rotation in its native membrane environment, without any genetic, chemical or mechanical modification of the enzyme, for the first time. The results suggest that a transmembrane AC field is able to synchronise the steps of ion-pumping in individual enzymes via a hold-and-release mechanism, which opens up the possibility of biotechnological exploitation. Our approach is likely to work for other transmembrane ion-transporting assemblies, not only rotary enzymes, to determine intrinsic in situ rates of ion pumping.
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Affiliation(s)
- Csilla-Maria Ferencz
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Pál Petrovszki
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - András Dér
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Zoltán Kóta
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
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Higashida H, Yokoyama S, Tsuji C, Muramatsu SI. Neurotransmitter release: vacuolar ATPase V0 sector c-subunits in possible gene or cell therapies for Parkinson's, Alzheimer's, and psychiatric diseases. J Physiol Sci 2017; 67:11-17. [PMID: 27289535 PMCID: PMC10717279 DOI: 10.1007/s12576-016-0462-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/27/2016] [Indexed: 12/13/2022]
Abstract
We overview the 16-kDa proteolipid mediatophore, the transmembrane c-subunit of the V0 sector of the vacuolar proton ATPase (ATP6V0C) that was shown to mediate the secretion of acetylcholine. Acetylcholine, serotonin, and dopamine (DA) are released from cell soma and/or dendrites if ATP6V0C is expressed in cultured cells. Adeno-associated viral vector-mediated gene transfer of ATP6V0C into the caudate putamen enhanced the depolarization-induced overflow of endogenous DA in Parkinson-model mice. Motor impairment was ameliorated in hemiparkinsonian model mice when ATP6V0C was expressed with DA-synthesizing enzymes. The review discusses application in the future as a potential tool for gene therapy, cell transplantation therapy, and inducible pluripotent stem cell therapy in neurological diseases, from the view point of recent findings regarding vacuolar ATPase.
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Affiliation(s)
- Haruhiro Higashida
- Kanazawa University Research Center for Child Mental Development, Kanazawa, 920-8640, Japan.
| | - Shigeru Yokoyama
- Kanazawa University Research Center for Child Mental Development, Kanazawa, 920-8640, Japan
| | - Chiharu Tsuji
- Kanazawa University Research Center for Child Mental Development, Kanazawa, 920-8640, Japan
| | - Shin-Ichi Muramatsu
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, 329-0498, Japan
- Center for Gene and Cell Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, 108-8639, Japan
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Huang L, Wickramasekara SI, Akinyeke T, Stewart BS, Jiang Y, Raber J, Maier CS. Ion mobility-enhanced MS(E)-based label-free analysis reveals effects of low-dose radiation post contextual fear conditioning training on the mouse hippocampal proteome. J Proteomics 2016; 140:24-36. [PMID: 27020882 PMCID: PMC5029422 DOI: 10.1016/j.jprot.2016.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 03/16/2016] [Accepted: 03/17/2016] [Indexed: 11/15/2022]
Abstract
UNLABELLED Recent advances in the field of biodosimetry have shown that the response of biological systems to ionizing radiation is complex and depends on the type and dose of radiation, the tissue(s) exposed, and the time lapsed after exposure. The biological effects of low dose radiation on learning and memory are not well understood. An ion mobility-enhanced data-independent acquisition (MS(E)) approach in conjunction with the ISOQuant software tool was utilized for label-free quantification of hippocampal proteins with the goal of determining protein alteration associated with low-dose whole body ionizing radiation (X-rays, 1Gy) of 5.5-month-old male C57BL/6J mice post contextual fear conditioning training. Global proteome analysis revealed deregulation of 73 proteins (out of 399 proteins). Deregulated proteins indicated adverse effects of irradiation on myelination and perturbation of energy metabolism pathways involving a shift from the TCA cycle to glutamate oxidation. Our findings also indicate that proteins associated with synaptic activity, including vesicle recycling and neurotransmission, were altered in the irradiated mice. The elevated LTP and decreased LTD suggest improved synaptic transmission and enhanced efficiency of neurotransmitter release which would be consistent with the observed comparable contextual fear memory performance of the mice following post-training whole body or sham-irradiation. SIGNIFICANCE This study is significant because the biological consequences of low dose radiation on learning and memory are complex and not yet well understood. We conducted a IMS-enhanced MS(E)-based label-free quantitative proteomic analysis of hippocampal tissue with the goal of determining protein alteration associated with low-dose whole body ionizing radiation (X-ray, 1Gy) of 5.5-month-old male C57BL/6J mice post contextual fear conditioning training. The IMS-enhanced MS(E) approach in conjunction with ISOQuant software was robust and accurate with low median CV values of 0.99% for the technical replicates of samples from both the sham and irradiated group. The biological variance was as low as 1.61% for the sham group and 1.31% for the irradiated group. The applied data generation and processing workflow allowed the quantitative evaluation of 399 proteins. The current proteomic analysis indicates that myelination is sensitive to low dose radiation. The observed protein level changes imply modulation of energy metabolism pathways in the radiation exposed group, specifically changes in protein abundance levels suggest a shift from TCA cycle to glutamate oxidation to satisfy energy demands. Most significantly, our study reveals deregulation of proteins involved in processes that govern synaptic activity including enhanced synaptic vesicle cycling, and altered long-term potentiation (LTP) and depression (LTD). An elevated LTP and decreased LTD suggest improved synaptic transmission and enhanced efficiency of neurotransmitter release which is consistent with the observed comparable contextual fear memory performance of the mice following post-training whole body or sham-irradiation. Overall, our results underscore the importance of low dose radiation experiments for illuminating the sensitivity of biochemical pathways to radiation, and the modulation of potential repair and compensatory response mechanisms. This kind of studies and associated findings may ultimately lead to the design of strategies for ameliorating hippocampal and CNS injury following radiation exposure as part of medical therapies or as a consequence of occupational hazards.
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Affiliation(s)
- Lin Huang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States
| | | | - Tunde Akinyeke
- Department of Behavioral Neuroscience, Division of Neuroscience, ONPRC, Oregon Health and Science University, Portland, Oregon 97239, United States
| | - Blair S Stewart
- Department of Behavioral Neuroscience, Division of Neuroscience, ONPRC, Oregon Health and Science University, Portland, Oregon 97239, United States
| | - Yuan Jiang
- Department of Statistics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Jacob Raber
- Department of Behavioral Neuroscience, Division of Neuroscience, ONPRC, Oregon Health and Science University, Portland, Oregon 97239, United States; Departments of Neurology and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health and Science University, Portland, Oregon 97239, United States
| | - Claudia S Maier
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, United States.
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Deranieh RM, Shi Y, Tarsio M, Chen Y, McCaffery JM, Kane PM, Greenberg ML. Perturbation of the Vacuolar ATPase: A NOVEL CONSEQUENCE OF INOSITOL DEPLETION. J Biol Chem 2015; 290:27460-72. [PMID: 26324718 DOI: 10.1074/jbc.m115.683706] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Indexed: 11/06/2022] Open
Abstract
Depletion of inositol has profound effects on cell function and has been implicated in the therapeutic effects of drugs used to treat epilepsy and bipolar disorder. We have previously shown that the anticonvulsant drug valproate (VPA) depletes inositol by inhibiting myo-inositol-3-phosphate synthase, the enzyme that catalyzes the first and rate-limiting step of inositol biosynthesis. To elucidate the cellular consequences of inositol depletion, we screened the yeast deletion collection for VPA-sensitive mutants and identified mutants in vacuolar sorting and the vacuolar ATPase (V-ATPase). Inositol depletion caused by starvation of ino1Δ cells perturbed the vacuolar structure and decreased V-ATPase activity and proton pumping in isolated vacuolar vesicles. VPA compromised the dynamics of phosphatidylinositol 3,5-bisphosphate (PI3,5P2) and greatly reduced V-ATPase proton transport in inositol-deprived wild-type cells. Osmotic stress, known to increase PI3,5P2 levels, did not restore PI3,5P2 homeostasis nor did it induce vacuolar fragmentation in VPA-treated cells, suggesting that perturbation of the V-ATPase is a consequence of altered PI3,5P2 homeostasis under inositol-limiting conditions. This study is the first to demonstrate that inositol depletion caused by starvation of an inositol synthesis mutant or by the inositol-depleting drug VPA leads to perturbation of the V-ATPase.
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Affiliation(s)
- Rania M Deranieh
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Yihui Shi
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - Maureen Tarsio
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Yan Chen
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202
| | - J Michael McCaffery
- the Integrated Imaging Center, Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218
| | - Patricia M Kane
- the Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York 13210, and
| | - Miriam L Greenberg
- From the Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202,
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Morel N, Poëa-Guyon S. The membrane domain of vacuolar H(+)ATPase: a crucial player in neurotransmitter exocytotic release. Cell Mol Life Sci 2015; 72:2561-73. [PMID: 25795337 PMCID: PMC11113229 DOI: 10.1007/s00018-015-1886-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 03/10/2015] [Accepted: 03/12/2015] [Indexed: 12/31/2022]
Abstract
V-ATPases are multimeric enzymes made of two sectors, a V1 catalytic domain and a V0 membrane domain. They accumulate protons in various intracellular organelles. Acidification of synaptic vesicles by V-ATPase energizes the accumulation of neurotransmitters in these storage organelles and is therefore required for efficient synaptic transmission. In addition to this well-accepted role, functional studies have unraveled additional hidden roles of V0 in neurotransmitter exocytosis that are independent of the transport of protons. V0 interacts with SNAREs and calmodulin, and perturbing these interactions affects neurotransmitter release. Here, we discuss these data in relation with previous results obtained in reconstituted membranes and on yeast vacuole fusion. We propose that V0 could be a sensor of intra-vesicular pH that controls the exocytotic machinery, probably regulating SNARE complex assembly during the synaptic vesicle priming step, and that, during the membrane fusion step, V0 might favor lipid mixing and fusion pore stability.
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Affiliation(s)
- Nicolas Morel
- Centre de Neurosciences Paris-Sud, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8195 and Université Paris-Sud, 91405, Orsay, France,
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15
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Kissing S, Hermsen C, Repnik U, Nesset CK, von Bargen K, Griffiths G, Ichihara A, Lee BS, Schwake M, De Brabander J, Haas A, Saftig P. Vacuolar ATPase in phagosome-lysosome fusion. J Biol Chem 2015; 290:14166-80. [PMID: 25903133 DOI: 10.1074/jbc.m114.628891] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Indexed: 01/11/2023] Open
Abstract
The vacuolar H(+)-ATPase (v-ATPase) complex is instrumental in establishing and maintaining acidification of some cellular compartments, thereby ensuring their functionality. Recently it has been proposed that the transmembrane V0 sector of v-ATPase and its a-subunits promote membrane fusion in the endocytic and exocytic pathways independent of their acidification functions. Here, we tested if such a proton-pumping independent role of v-ATPase also applies to phagosome-lysosome fusion. Surprisingly, endo(lyso)somes in mouse embryonic fibroblasts lacking the V0 a3 subunit of the v-ATPase acidified normally, and endosome and lysosome marker proteins were recruited to phagosomes with similar kinetics in the presence or absence of the a3 subunit. Further experiments used macrophages with a knockdown of v-ATPase accessory protein 2 (ATP6AP2) expression, resulting in a strongly reduced level of the V0 sector of the v-ATPase. However, acidification appeared undisturbed, and fusion between latex bead-containing phagosomes and lysosomes, as analyzed by electron microscopy, was even slightly enhanced, as was killing of non-pathogenic bacteria by V0 mutant macrophages. Pharmacologically neutralized lysosome pH did not affect maturation of phagosomes in mouse embryonic cells or macrophages. Finally, locking the two large parts of the v-ATPase complex together by the drug saliphenylhalamide A did not inhibit in vitro and in cellulo fusion of phagosomes with lysosomes. Hence, our data do not suggest a fusion-promoting role of the v-ATPase in the formation of phagolysosomes.
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Affiliation(s)
- Sandra Kissing
- From the Institute of Biochemistry, Christian-Albrechts-University of Kiel, D-24098 Kiel, Germany
| | - Christina Hermsen
- Institute for Cell Biology, Friedrich-Wilhelms University, D-53121 Bonn, Germany
| | - Urska Repnik
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | | | - Kristine von Bargen
- Institute for Cell Biology, Friedrich-Wilhelms University, D-53121 Bonn, Germany
| | - Gareth Griffiths
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Atsuhiro Ichihara
- Department of Medicine II, Tokyo Women's Medical University, Tokyo 162-866, Japan
| | - Beth S Lee
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio 42210
| | - Michael Schwake
- Department of Chemistry, Biochemistry III, University of Bielefeld, D-33615 Bielefeld, Germany, and
| | - Jef De Brabander
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Albert Haas
- Institute for Cell Biology, Friedrich-Wilhelms University, D-53121 Bonn, Germany,
| | - Paul Saftig
- From the Institute of Biochemistry, Christian-Albrechts-University of Kiel, D-24098 Kiel, Germany,
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16
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Nabatov AA. The vesicle-associated function of NOD2 as a link between Crohn's disease and mycobacterial infection. Gut Pathog 2015; 7:1. [PMID: 25653718 PMCID: PMC4316803 DOI: 10.1186/s13099-015-0049-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/03/2015] [Indexed: 12/18/2022] Open
Abstract
Although Crohn’s disease (CD) etiology remains unclear, a growing body of evidence suggests that CD may include an infectious component, with Mycobacterium avium subsp. paratuberculosis (MAP) being the most likely candidate for this role. However, the molecular mechanism of the MAP involvement in CD pathogenesis remains unclear. The polymorphism of the NOD2 gene, coding for an intracellular pattern recognition receptor, is a factor of predisposition to mycobacterial infections and CD. Recent findings on NOD2 interactions and functions provide the missing pieces in the puzzle of a NOD2-mediated mechanism common for mycobacterial infections and CD. Implications of these new findings for the development of a better understanding and treatments of CD and mycobacterial infections are discussed.
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Affiliation(s)
- Alexey A Nabatov
- Maastricht Radiation Oncology, MAASTRO/GROW Maastricht University Medical Center+, PO Box 616, 6200 MD Maastricht, The Netherlands ; Science Center, Volga Region State Academy of Physical Culture, Sport and Tourism, 33, Universiade Village, Kazan, 420138 Russia
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17
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Abstract
Synaptic vesicles release their vesicular contents to the extracellular space by Ca(2+)-triggered exocytosis. The Ca(2+)-triggered exocytotic process is regulated by synaptotagmin (Syt), a vesicular Ca(2+)-binding C2 domain protein. Synaptotagmin 1 (Syt1), the most studied major isoform among 16 Syt isoforms, mediates Ca(2+)-triggered synaptic vesicle exocytosis by interacting with the target membranes and SNARE/complexin complex. In synapses of the central nervous system, synaptobrevin 2, a major vesicular SNARE protein, forms a ternary SNARE complex with the plasma membrane SNARE proteins, syntaxin 1 and SNAP25. The affinities of Ca(2+)-dependent interactions between Syt1 and its targets (i.e., SNARE complexes and membranes) are well correlated with the efficacies of the corresponding exocytotic processes. Therefore, different SNARE protein isoforms and membrane lipids, which interact with Syt1 with various affinities, are capable of regulating the efficacy of Syt1-mediated exocytosis. Otoferlin, another type of vesicular C2 domain protein that binds to the membrane in a Ca(2+)-dependent manner, is also involved in the Ca(2+)-triggered synaptic vesicle exocytosis in auditory hair cells. However, the functions of otoferlin in the exocytotic process are not well understood. In addition, at least five different types of synaptic vesicle proteins such as synaptic vesicle protein 2, cysteine string protein α, rab3, synapsin, and a group of proteins containing four transmembrane regions, which includes synaptophysin, synaptogyrin, and secretory carrier membrane protein, are involved in modulating the exocytotic process by regulating the formation and trafficking of synaptic vesicles.
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Affiliation(s)
- Ok-Ho Shin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas
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18
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Vibrio effector protein VopQ inhibits fusion of V-ATPase-containing membranes. Proc Natl Acad Sci U S A 2014; 112:100-5. [PMID: 25453092 DOI: 10.1073/pnas.1413764111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vesicle fusion governs many important biological processes, and imbalances in the regulation of membrane fusion can lead to a variety of diseases such as diabetes and neurological disorders. Here we show that the Vibrio parahaemolyticus effector protein VopQ is a potent inhibitor of membrane fusion based on an in vitro yeast vacuole fusion model. Previously, we demonstrated that VopQ binds to the V(o) domain of the conserved V-type H(+)-ATPase (V-ATPase) found on acidic compartments such as the yeast vacuole. VopQ forms a nonspecific, voltage-gated membrane channel of 18 Å resulting in neutralization of these compartments. We now present data showing that VopQ inhibits yeast vacuole fusion. Furthermore, we identified a unique mutation in VopQ that delineates its two functions, deacidification and inhibition of membrane fusion. The use of VopQ as a membrane fusion inhibitor in this manner now provides convincing evidence that vacuole fusion occurs independently of luminal acidification in vitro.
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19
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Mangieri LR, Mader BJ, Thomas CE, Taylor CA, Luker AM, Tse TE, Huisingh C, Shacka JJ. ATP6V0C knockdown in neuroblastoma cells alters autophagy-lysosome pathway function and metabolism of proteins that accumulate in neurodegenerative disease. PLoS One 2014; 9:e93257. [PMID: 24695574 PMCID: PMC3973706 DOI: 10.1371/journal.pone.0093257] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 02/22/2014] [Indexed: 02/06/2023] Open
Abstract
ATP6V0C is the bafilomycin A1-binding subunit of vacuolar ATPase, an enzyme complex that critically regulates vesicular acidification. We and others have shown previously that bafilomycin A1 regulates cell viability, autophagic flux and metabolism of proteins that accumulate in neurodegenerative disease. To determine the importance of ATP6V0C for autophagy-lysosome pathway function, SH-SY5Y human neuroblastoma cells differentiated to a neuronal phenotype were nucleofected with non-target or ATP6V0C siRNA and following recovery were treated with either vehicle or bafilomycin A1 (0.3-100 nM) for 48 h. ATP6V0C knockdown was validated by quantitative RT-PCR and by a significant decrease in Lysostracker Red staining. ATP6V0C knockdown significantly increased basal levels of microtubule-associated protein light chain 3-II (LC3-II), α-synuclein high molecular weight species and APP C-terminal fragments, and inhibited autophagic flux. Enhanced LC3 and LAMP-1 co-localization following knockdown suggests that autophagic flux was inhibited in part due to lysosomal degradation and not by a block in vesicular fusion. Knockdown of ATP6V0C also sensitized cells to the accumulation of autophagy substrates and a reduction in neurite length following treatment with 1 nM bafilomycin A1, a concentration that did not produce such alterations in non-target control cells. Reduced neurite length and the percentage of propidium iodide-positive dead cells were also significantly greater following treatment with 3 nM bafilomycin A1. Together these results indicate a role for ATP6V0C in maintaining constitutive and stress-induced ALP function, in particular the metabolism of substrates that accumulate in age-related neurodegenerative disease and may contribute to disease pathogenesis.
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Affiliation(s)
- Leandra R. Mangieri
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Burton J. Mader
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Birmingham Veterans Administration Medical Center, Birmingham, Alabama, United States of America
| | - Cailin E. Thomas
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Charles A. Taylor
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Austin M. Luker
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Tonia E. Tse
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Carrie Huisingh
- Department Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - John J. Shacka
- Department Pathology, Neuropathology Division, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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20
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Poëa-Guyon S, Ammar MR, Erard M, Amar M, Moreau AW, Fossier P, Gleize V, Vitale N, Morel N. The V-ATPase membrane domain is a sensor of granular pH that controls the exocytotic machinery. ACTA ACUST UNITED AC 2013; 203:283-98. [PMID: 24165939 PMCID: PMC3812966 DOI: 10.1083/jcb.201303104] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Several studies have suggested that the V0 domain of the vacuolar-type H(+)-adenosine triphosphatase (V-ATPase) is directly implicated in secretory vesicle exocytosis through a role in membrane fusion. We report in this paper that there was a rapid decrease in neurotransmitter release after acute photoinactivation of the V0 a1-I subunit in neuronal pairs. Likewise, inactivation of the V0 a1-I subunit in chromaffin cells resulted in a decreased frequency and prolonged kinetics of amperometric spikes induced by depolarization, with shortening of the fusion pore open time. Dissipation of the granular pH gradient was associated with an inhibition of exocytosis and correlated with the V1-V0 association status in secretory granules. We thus conclude that V0 serves as a sensor of intragranular pH that controls exocytosis and synaptic transmission via the reversible dissociation of V1 at acidic pH. Hence, the V-ATPase membrane domain would allow the exocytotic machinery to discriminate fully loaded and acidified vesicles from vesicles undergoing neurotransmitter reloading.
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Affiliation(s)
- Sandrine Poëa-Guyon
- Centre de Neurosciences Paris-Sud, Centre National de la Recherche Scientifique Unité Mixte de Recherche 8195 and Université Paris-Sud, F-91405 Orsay, France
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21
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Corena-McLeod M, Walss-Bass C, Oliveros A, Gordillo Villegas A, Ceballos C, Charlesworth CM, Madden B, Linser PJ, Van Ekeris L, Smith K, Richelson E. New model of action for mood stabilizers: phosphoproteome from rat pre-frontal cortex synaptoneurosomal preparations. PLoS One 2013; 8:e52147. [PMID: 23690912 PMCID: PMC3653908 DOI: 10.1371/journal.pone.0052147] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 11/09/2012] [Indexed: 01/11/2023] Open
Abstract
Background Mitochondrial short and long-range movements are necessary to generate the energy needed for synaptic signaling and plasticity. Therefore, an effective mechanism to transport and anchor mitochondria to pre- and post-synaptic terminals is as important as functional mitochondria in neuronal firing. Mitochondrial movement range is regulated by phosphorylation of cytoskeletal and motor proteins in addition to changes in mitochondrial membrane potential. Movement direction is regulated by serotonin and dopamine levels. However, data on mitochondrial movement defects and their involvement in defective signaling and neuroplasticity in relationship with mood disorders is scarce. We have previously reported the effects of lithium, valproate and a new antipsychotic, paliperidone on protein expression levels at the synaptic level. Hypothesis Mitochondrial function defects have recently been implicated in schizophrenia and bipolar disorder. We postulate that mood stabilizer treatment has a profound effect on mitochondrial function, synaptic plasticity, mitochondrial migration and direction of movement. Methods Synaptoneurosomal preparations from rat pre-frontal cortex were obtained after 28 daily intraperitoneal injections of lithium, valproate and paliperidone. Phosphorylated proteins were identified using 2D-DIGE and nano LC-ESI tandem mass spectrometry. Results Lithium, valproate and paliperidone had a substantial and common effect on the phosphorylation state of specific actin, tubulin and myosin isoforms as well as other proteins associated with neurofilaments. Furthermore, different subunits from complex III and V of the electron transfer chain were heavily phosphorylated by treatment with these drugs indicating selective phosphorylation. Conclusions Mood stabilizers have an effect on mitochondrial function, mitochondrial movement and the direction of this movement. The implications of these findings will contribute to novel insights regarding clinical treatment and the mode of action of these drugs.
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The zebrafish mutants for the V-ATPase subunits d, ac45, E, H and c and their variable pigment dilution phenotype. BMC Res Notes 2013; 6:39. [PMID: 23375000 PMCID: PMC3599454 DOI: 10.1186/1756-0500-6-39] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 01/23/2013] [Indexed: 11/10/2022] Open
Abstract
Background The V-ATPase is a proton pump that creates an acidic medium, necessary for lysosome function and vesicular traffic. It is also essential for several developmental processes. Many enzymes, like the V-ATPase, are assemblies of multiple subunits, in which each one performs a specific function required to achieve full activity. In the zebrafish V-ATPase 15 different subunits form this multimeric complex and mutations in any of these subunits induce hypopigmentation or pigment dilution phenotype. We have previously found variability in the pigment dilution phenotype among five of the V-ATPase zebrafish mutants. This work presents additional information about such differences and is an update from a previous report. Findings We describe the variable phenotype severity observed among zebrafish V-ATPase pigment dilution mutants studying mRNA expression levels from their corresponding genes. At the same time we carried out phylogenetic analysis for this genes. Conclusions Based in the similarities between different pigment dilution mutants we suggest that there is an essential role for V-ATPases in melanosome biogenesis and melanocyte survival. Neither variable expression levels for the different V-ATPase subunits studied here or the presence of duplicated genes seems to account for the variable phenotype severity from this group of mutants. We believe there are some similarities between the pigment dilution phenotype from zebrafish V-ATPase insertional mutants and pigment mutants obtained in a chemical screening (“Tubingen pigmentation mutants”). As for some of these “Tubingen mutants” the mutated gene has not been found we suggest that mutations in V-ATPase genes may be inducing their defects.
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23
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Ferencz C, Petrovszki P, Kóta Z, Fodor-Ayaydin E, Haracska L, Bóta A, Varga Z, Dér A, Marsh D, Páli T. Estimating the rotation rate in the vacuolar proton-ATPase in native yeast vacuolar membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:147-58. [PMID: 23160754 DOI: 10.1007/s00249-012-0871-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/10/2012] [Accepted: 10/25/2012] [Indexed: 11/25/2022]
Abstract
The rate of rotation of the rotor in the yeast vacuolar proton-ATPase (V-ATPase), relative to the stator or steady parts of the enzyme, is estimated in native vacuolar membrane vesicles from Saccharomyces cerevisiae under standardised conditions. Membrane vesicles are formed spontaneously after exposing purified yeast vacuoles to osmotic shock. The fraction of total ATPase activity originating from the V-ATPase is determined by using the potent and specific inhibitor of the enzyme, concanamycin A. Inorganic phosphate liberated from ATP in the vacuolar membrane vesicle system, during ten min of ATPase activity at 20 °C, is assayed spectrophotometrically for different concanamycin A concentrations. A fit of the quadratic binding equation, assuming a single concanamycin A binding site on a monomeric V-ATPase (our data are incompatible with models assuming multiple binding sites), to the inhibitor titration curve determines the concentration of the enzyme. Combining this with the known ATP/rotation stoichiometry of the V-ATPase and the assayed concentration of inorganic phosphate liberated by the V-ATPase, leads to an average rate of ~10 Hz for full 360° rotation (and a range of 6-32 Hz, considering the ± standard deviation of the enzyme concentration), which, from the time-dependence of the activity, extrapolates to ~14 Hz (8-48 Hz) at the beginning of the reaction. These are lower-limit estimates. To our knowledge, this is the first report of the rotation rate in a V-ATPase that is not subjected to genetic or chemical modification and is not fixed to a solid support; instead it is functioning in its native membrane environment.
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Affiliation(s)
- Csilla Ferencz
- Institute of Biophysics, Biological Research Centre, Temesvári krt. 62, 6726, Szeged, Hungary
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Usenovic M, Knight AL, Ray A, Wong V, Brown KR, Caldwell GA, Caldwell KA, Stagljar I, Krainc D. Identification of novel ATP13A2 interactors and their role in α-synuclein misfolding and toxicity. Hum Mol Genet 2012; 21:3785-94. [PMID: 22645275 DOI: 10.1093/hmg/dds206] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lysosomes are responsible for degradation and recycling of bulky cell material, including accumulated misfolded proteins and dysfunctional organelles. Increasing evidence implicates lysosomal dysfunction in several neurodegenerative disorders, including Parkinson's disease and related synucleinopathies, which are characterized by the accumulation of α-synuclein (α-syn) in Lewy bodies. Studies of lysosomal proteins linked to neurodegenerative disorders present an opportunity to uncover specific molecular mechanisms and pathways that contribute to neurodegeneration. Loss-of-function mutations in a lysosomal protein, ATP13A2 (PARK9), cause Kufor-Rakeb syndrome that is characterized by early-onset parkinsonism, pyramidal degeneration and dementia. While loss of ATP13A2 function plays a role in α-syn misfolding and toxicity, the normal function of ATP13A2 in the brain remains largely unknown. Here, we performed a screen to identify ATP13A2 interacting partners, as a first step toward elucidating its function. Utilizing a split-ubiquitin membrane yeast two-hybrid system that was developed to identify interacting partners of full-length integral membrane proteins, we identified 43 novel interactors that primarily implicate ATP13A2 in cellular processes such as endoplasmic reticulum (ER) translocation, ER-to-Golgi trafficking and vesicular transport and fusion. We showed that a subset of these interactors modified α-syn aggregation and α-syn-mediated degeneration of dopaminergic neurons in Caenorhabditis elegans, further suggesting that ATP13A2 and α-syn are functionally linked in neurodegeneration. These results implicate ATP13A2 in vesicular trafficking and provide a platform for further studies of ATP13A2 in neurodegeneration.
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Affiliation(s)
- Marija Usenovic
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, MassGeneral Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
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Chan CY, Prudom C, Raines SM, Charkhzarrin S, Melman SD, De Haro LP, Allen C, Lee SA, Sklar LA, Parra KJ. Inhibitors of V-ATPase proton transport reveal uncoupling functions of tether linking cytosolic and membrane domains of V0 subunit a (Vph1p). J Biol Chem 2012; 287:10236-10250. [PMID: 22215674 DOI: 10.1074/jbc.m111.321133] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Vacuolar ATPases (V-ATPases) are important for many cellular processes, as they regulate pH by pumping cytosolic protons into intracellular organelles. The cytoplasm is acidified when V-ATPase is inhibited; thus we conducted a high-throughput screen of a chemical library to search for compounds that acidify the yeast cytosol in vivo using pHluorin-based flow cytometry. Two inhibitors, alexidine dihydrochloride (EC(50) = 39 μM) and thonzonium bromide (EC(50) = 69 μM), prevented ATP-dependent proton transport in purified vacuolar membranes. They acidified the yeast cytosol and caused pH-sensitive growth defects typical of V-ATPase mutants (vma phenotype). At concentrations greater than 10 μM the inhibitors were cytotoxic, even at the permissive pH (pH 5.0). Membrane fractions treated with alexidine dihydrochloride and thonzonium bromide fully retained concanamycin A-sensitive ATPase activity despite the fact that proton translocation was inhibited by 80-90%, indicating that V-ATPases were uncoupled. Mutant V-ATPase membranes lacking residues 362-407 of the tether of Vph1p subunit a of V(0) were resistant to thonzonium bromide but not to alexidine dihydrochloride, suggesting that this conserved sequence confers uncoupling potential to V(1)V(0) complexes and that alexidine dihydrochloride uncouples the enzyme by a different mechanism. The inhibitors also uncoupled the Candida albicans enzyme and prevented cell growth, showing further specificity for V-ATPases. Thus, a new class of V-ATPase inhibitors (uncouplers), which are not simply ionophores, provided new insights into the enzyme mechanism and original evidence supporting the hypothesis that V-ATPases may not be optimally coupled in vivo. The consequences of uncoupling V-ATPases in vivo as potential drug targets are discussed.
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Affiliation(s)
- Chun-Yuan Chan
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Catherine Prudom
- Center for Molecular Discovery, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Summer M Raines
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Sahba Charkhzarrin
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Sandra D Melman
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Leyma P De Haro
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Chris Allen
- Center for Molecular Discovery, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Samuel A Lee
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Larry A Sklar
- Center for Molecular Discovery, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131; Department of Pathology and Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131
| | - Karlett J Parra
- Department of Biochemistry and Molecular Biology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131.
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Qin A, Cheng TS, Lin Z, Pavlos NJ, Jiang Q, Xu J, Dai KR, Zheng MH. Versatile roles of V-ATPases accessory subunit Ac45 in osteoclast formation and function. PLoS One 2011; 6:e27155. [PMID: 22087256 PMCID: PMC3210823 DOI: 10.1371/journal.pone.0027155] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 10/11/2011] [Indexed: 11/25/2022] Open
Abstract
Vacuolar-type H(+)-ATPases (V-ATPases) are macromolecular proton pumps that acidify intracellular cargos and deliver protons across the plasma membrane of a variety of specialized cells, including bone-resorbing osteoclasts. Extracellular acidification is crucial for osteoclastic bone resorption, a process that initiates the dissolution of mineralized bone matrix. While the importance of V-ATPases in osteoclastic resorptive function is well-defined, whether V-ATPases facilitate additional aspects of osteoclast function and/or formation remains largely obscure. Here we report that the V-ATPase accessory subunit Ac45 participates in both osteoclast formation and function. Using a siRNA-based approach, we show that targeted suppression of Ac45 impairs intracellular acidification and endocytosis, both are prerequisite for osteoclastic bone resorptive function in vitro. Interestingly, we find that knockdown of Ac45 also attenuates osteoclastogenesis owing to a reduced fusion capacity of osteoclastic precursor cells. Finally, in an effort to gain more detailed insights into the functional role of Ac45 in osteoclasts, we attempted to generate osteoclast-specific Ac45 conditional knockout mice using a Cathepsin K-Cre-LoxP system. Surprisingly, however, insertion of the neomycin cassette in the Ac45-Flox(Neo) mice resulted in marked disturbances in CNS development and ensuing embryonic lethality thus precluding functional assessment of Ac45 in osteoclasts and peripheral bone tissues. Based on these unexpected findings we propose that, in addition to its canonical function in V-ATPase-mediated acidification, Ac45 plays versatile roles during osteoclast formation and function.
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Affiliation(s)
- An Qin
- Shanghai Key Laboratory of Orthopaedic Implant, Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine, Ninth People's Hospital, Shanghai, The People's Republic of China
- Centre for Orthopaedic Research, School of Surgery, The University of Western Australia, Perth, Australia
| | - Tak S. Cheng
- Centre for Orthopaedic Research, School of Surgery, The University of Western Australia, Perth, Australia
| | - Zhen Lin
- Centre for Orthopaedic Research, School of Surgery, The University of Western Australia, Perth, Australia
- Division of Orthopaedic, Department of Surgery, Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangdong, The People's Republic of China
| | - Nathan J. Pavlos
- Centre for Orthopaedic Research, School of Surgery, The University of Western Australia, Perth, Australia
| | - Qing Jiang
- Australian-China Joint Centre for Bone and Joint Research, Model Animal Research Centre of Nanjing University, Nanjing, The People's Republic of China
- The Center of Diagnosis and Treatment for Joint Disease, Drum Tower Hospital Affiliated to Medical School of Nanjing University, Nanjing, The People's Republic of China
| | - Jiake Xu
- School of Pathology and Laboratory Medicine, The University of Western Australia, Perth, Australia
| | - Ke R. Dai
- Shanghai Key Laboratory of Orthopaedic Implant, Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine, Ninth People's Hospital, Shanghai, The People's Republic of China
- Orthopaedic Cellular and Molecular Biology Laboratory, Institute of Health Sciences, School of Medicine, Chinese Academy of Sciences, Shanghai Jiao Tong University, Shanghai, The People's Republic of China
| | - Ming H. Zheng
- Centre for Orthopaedic Research, School of Surgery, The University of Western Australia, Perth, Australia
- Australian-China Joint Centre for Bone and Joint Research, Model Animal Research Centre of Nanjing University, Nanjing, The People's Republic of China
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The V-ATPase proteolipid cylinder promotes the lipid-mixing stage of SNARE-dependent fusion of yeast vacuoles. EMBO J 2011; 30:4126-41. [PMID: 21934648 DOI: 10.1038/emboj.2011.335] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 08/19/2011] [Indexed: 01/13/2023] Open
Abstract
The V-ATPase V(0) sector associates with the peripheral V(1) sector to form a proton pump. V(0) alone has an additional function, facilitating membrane fusion in the endocytic and late exocytic pathways. V(0) contains a hexameric proteolipid cylinder, which might support fusion as proposed in proteinaceous pore models. To test this, we randomly mutagenized proteolipids. We recovered alleles that preserve proton translocation, normal SNARE activation and trans-SNARE pairing but that impair lipid and content mixing. Critical residues were found in all subunits of the proteolipid ring. They concentrate within the bilayer, close to the ring subunit interfaces. The fusion-impairing proteolipid substitutions stabilize the interaction of V(0) with V(1). Deletion of the vacuolar v-SNARE Nyv1 has the same effect, suggesting that both types of mutations similarly alter the conformation of V(0). Also covalent linkage of subunits in the proteolipid cylinder blocks vacuole fusion. We propose that a SNARE-dependent conformational change in V(0) proteolipids might stimulate fusion by creating a hydrophobic crevice that promotes lipid reorientation and formation of a lipidic fusion pore.
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